JP5635802B2 - Internal combustion engine drive control method and greenhouse cultivation system - Google Patents

Description

  The present invention relates to a driving control method for an internal combustion engine that supplies hydrocarbons with exhaust gas containing carbon dioxide to a greenhouse through an exhaust gas flow path having an exhaust gas purification unit, and exhaust from a combustion apparatus using hydrocarbons as fuel. The present invention relates to a greenhouse cultivation system having an exhaust gas flow path for supplying exhaust gas containing carbon dioxide to a plant in a greenhouse space.

  In recent years, cogeneration has been widely adopted, thereby improving energy efficiency and reducing carbon dioxide emissions that cause global warming. Cogeneration uses power and heat generated during power generation as an energy source, and there is another form of trigeneration that effectively uses carbon dioxide generated at this time and discarded in the past.

  Since the exhaust gas is obtained by burning hydrocarbon fuel such as LP gas and city gas in addition to heavy oil and kerosene, it contains carbon dioxide at a higher concentration than in the atmosphere. Trigeneration purifies exhaust gas emitted from internal combustion engines such as gas engines, and actively promotes the growth of plants using carbon dioxide contained in the exhaust gas as one of the raw materials for photosynthesis in the greenhouse. It is used for a greenhouse cultivation system for the purpose (see Patent Documents 1 and 2).

JP 2008-201649 A JP 2004-344154 A

  As a suitable growing environment for plants in a greenhouse, it is said that it is preferable to have carbon dioxide with a certain level of high concentration (700 ppm to 1500 ppm) from the viewpoint of forcing cultivation and the like. However, in order to improve the driving efficiency of the internal combustion engine, when it is driven by lean combustion and the exhaust gas generated is supplied to the greenhouse, the exhaust gas is small in the lean combustion, but the exhaust gas is not preferable for the growth of plants. There is a problem that nitrogen oxides exceeding the allowable limit are contained, and even if a catalyst is used to remove such nitrogen oxides from exhaust gas, it is difficult to sufficiently reduce the nitrogen oxide concentration. there were. In addition, when the internal combustion engine is driven by stoichiometric combustion with priority given to sufficiently reducing the nitrogen oxide concentration, the nitrogen oxide contained in the exhaust gas can be removed by the three-way catalyst, but the internal combustion engine is driven. There is a problem that the efficiency is lowered, and it has been difficult to achieve both improvement in driving efficiency of the internal combustion engine and reduction in nitrogen oxide concentration.

  In view of the above circumstances, an object of the present invention is to provide an internal combustion engine drive control method and a greenhouse cultivation system that can reduce the nitrogen oxide concentration in exhaust gas supplied to a greenhouse while maintaining high drive efficiency of the internal combustion engine. Is to provide.

〔Constitution〕
In order to achieve the above object, the characteristic configuration of the internal combustion engine drive control method of the present invention is to supply hydrocarbons to a greenhouse by burning hydrocarbons and exhausting carbon dioxide through an exhaust gas flow path having an exhaust gas purification unit. As a drive control method for an internal combustion engine,
When the carbon dioxide concentration in the greenhouse is lower than the carbon dioxide concentration range required in the greenhouse and the nitrogen oxide concentration in the greenhouse is equal to or higher than the nitrogen oxide concentration range required in the greenhouse, the internal combustion engine While supplying to the greenhouse via an exhaust gas flow path provided with an exhaust gas purification unit provided with a three-way catalyst for purifying exhaust gas from the internal combustion engine,
When the carbon dioxide concentration in the greenhouse is lower than the carbon dioxide concentration range required in the greenhouse and the nitrogen oxide concentration in the greenhouse is lower than the nitrogen oxide concentration range required in the greenhouse, the internal combustion The engine is driven by lean combustion, and is supplied to the greenhouse via an exhaust gas flow path provided with an exhaust gas purification unit provided with an oxidation catalyst for removing carbon monoxide from the internal combustion engine .

[Function and effect]
In other words, when driving an internal combustion engine, if stoichiometric combustion driving is performed, exhaust gas with a low concentration of nitrogen oxides can be supplied, and conversely, if lean combustion driving is performed, nitrogen oxides in exhaust gas introduced into the greenhouse However, the internal combustion engine can be driven in an efficient driving state.

  In the greenhouse, the concentration of carbon dioxide decreases due to carbon dioxide consumption by plants and inevitable ventilation conditions from inside the greenhouse to outside the greenhouse. And when carbon dioxide concentration falls, the carbon dioxide concentration in the said greenhouse can be raised by introduce | transducing the exhaust gas of the said internal combustion engine. At this time, the nitrogen oxide concentration in the greenhouse also increases, but if the increase is low, the internal combustion engine is preferably driven by a driving method with high driving efficiency, that is, driven by lean combustion. Can do.

  Furthermore, when supplying nitrogen dioxide, if the nitrogen oxide concentration in the greenhouse rises, the nitrogen oxide concentration in the greenhouse rises and begins to adversely affect plants. It is preferable to supply exhaust gas having a low oxide concentration. Therefore, the internal combustion engine only needs to be operated so that the concentration of nitrogen oxides in the exhaust gas becomes low, even when the driving efficiency is sacrificed, when such an environment is reached. That is, at this time, the internal combustion engine is driven by stoichiometric combustion.

Thus, when the carbon dioxide concentration in the greenhouse is lower than the carbon dioxide concentration range required in the greenhouse and the nitrogen oxide concentration in the greenhouse is equal to or greater than the nitrogen oxide concentration range required in the greenhouse. The internal combustion engine drive method is stoichiometric combustion drive , the carbon dioxide concentration in the greenhouse is lower than the carbon dioxide concentration range required in the greenhouse, and the nitrogen oxide concentration in the greenhouse is determined in the greenhouse. An operating method of an internal combustion engine that suppresses a reduction in operating efficiency and suppresses a nitrogen oxide concentration of exhaust gas supplied to a greenhouse to a low level by driving a lean burn when the concentration is lower than a nitrogen oxide concentration range. Can be realized.

  In each combustion state of the internal combustion engine, the nitrogen oxide concentration in the exhaust gas is preferably reduced as much as possible until it is introduced into the greenhouse. Oxides are reduced. However, in general, removal of nitrogen oxides from exhaust gas generated by lean combustion has a limited number of applicable nitrogen oxide removal means compared with the case of considering removal of nitrogen oxides from exhaust gas generated by stoichiometric combustion. Tend to be low. Therefore, even when nitrogen oxides in the exhaust gas are reduced, exhaust gas having a lower nitrogen oxide concentration can be supplied when the internal combustion engine is stoichiometrically burned than when lean combustion is performed. .

Further, since the are allowed to flow exhaust gas generated from the internal combustion engine in the exhaust gas line provided with an exhaust gas purifying catalyst suitable for each combustion state according to the combustion driving state of the internal combustion engine, the stoichiometric combustion from the gas Nitrogen oxide and carbon monoxide can be removed, and in lean combustion, carbon monoxide can be removed from the exhaust gas. In addition, lean combustion is a combustion method in which the concentration of nitrogen oxides contained in the exhaust gas is relatively low. Therefore, in any combustion driving state of the internal combustion engine, the exhaust gas supplied to the greenhouse has a sufficiently low concentration of nitrogen oxides. The exhaust gas can be supplied in an environment where the concentration of nitrogen oxides is difficult to increase.

〔Constitution〕
In addition, when the carbon dioxide concentration in the greenhouse is not lower than the carbon dioxide concentration range required in the greenhouse, the exhaust gas when the internal combustion engine is driven by lean combustion is placed in a space other than the greenhouse. It is preferable that an exhaust part for discharging is provided.

[Function and effect]
In the above configuration, when the exhaust gas from the internal combustion engine is supplied when the carbon dioxide concentration is less than or equal to the appropriate concentration in the greenhouse, the carbon dioxide concentration can be increased to an appropriate value, and the carbon dioxide concentration is an appropriate value. When the supply of the exhaust gas is stopped, the concentration of carbon dioxide recovers to an appropriate value as the carbon dioxide is consumed.

  Therefore, when the carbon dioxide concentration in the greenhouse is not lower than the carbon dioxide concentration range required in the greenhouse and there is a sufficient amount of carbon dioxide in the greenhouse, it is not necessary to introduce exhaust gas into the greenhouse. The internal combustion engine is preferably driven by a driving method with high driving efficiency and emits exhaust gas to a space other than inside the greenhouse. In other words, the internal combustion engine is driven by lean combustion and emits exhaust gas from the exhaust section. preferable. By driving the internal combustion engine in this way, it is possible to maintain the carbon dioxide concentration in the greenhouse in an appropriate concentration range while operating the internal combustion engine with high efficiency.

〔Constitution〕
The characteristic configuration of the greenhouse cultivation system of the present invention is a greenhouse cultivation system provided with an exhaust gas flow path for supplying exhaust gas containing carbon dioxide discharged from an internal combustion engine fueled with hydrocarbons to plants in the greenhouse space. And
The internal combustion engine is configured to be switchable between a lean combustion operation and a stoichiometric combustion operation,
A lean combustion exhaust gas channel and a stoichiometric combustion exhaust gas channel are provided in the exhaust gas channel,
An exhaust gas flow path switching unit that switches between the lean combustion exhaust gas flow path and the stoichiometric combustion exhaust gas flow path according to the combustion operation state of the internal combustion engine,
An exhaust gas purification unit provided with an oxidation catalyst in the lean combustion exhaust gas channel, and an exhaust gas purification unit provided with a three-way catalyst in the stoichiometric combustion exhaust gas channel,
While providing a carbon dioxide concentration detector and a nitrogen oxide detector in the greenhouse,
Based on the detection output from the carbon dioxide concentration detector and the nitrogen oxide detector, the carbon dioxide concentration in the greenhouse is lower than the carbon dioxide concentration range required in the greenhouse, and the nitrogen oxide concentration in the greenhouse Is provided with a switching control unit that switches the internal combustion engine to stoichiometric combustion when it is above the nitrogen oxide concentration range required in the greenhouse, and to switch the internal combustion engine to lean combustion drive otherwise It is in.

[Function and effect]
Since it has an exhaust gas flow path for supplying exhaust gas containing carbon dioxide emitted from an internal combustion engine fueled with hydrocarbons to plants in the greenhouse space, the carbon dioxide in the exhaust gas is supplied, and the greenhouse has a high concentration of carbon dioxide. Plants can be cultivated as an environment containing carbon.

  At this time, when the exhaust gas is supplied, if the internal combustion engine is configured to be switchable between a lean combustion operation and a stoichiometric combustion operation, the internal combustion engine performs a lean combustion operation with high operating efficiency and a relatively clean exhaust gas. The operation mode of the internal combustion engine can be switched according to the exhaust gas supply needs.

  Further, the exhaust gas flow path is provided with a lean combustion exhaust gas flow path and a stoichiometric combustion exhaust gas flow path, and the exhaust gas switching between the lean combustion exhaust gas flow path and the stoichiometric combustion exhaust gas flow path according to the combustion operation state of the internal combustion engine By providing the flow path switching unit, the generated exhaust gas can be supplied to the greenhouse through different flow paths in each operation driving state of the internal combustion engine, and an oxidation catalyst is provided in the lean combustion exhaust gas flow path. In the stoichiometric combustion, nitrogen oxides are emitted from the exhaust gas by a catalyst suitable for the operation driving state of the internal combustion engine. And carbon monoxide are removed. In lean combustion, carbon monoxide is removed. Furthermore, since lean combustion is a combustion system in which the concentration of nitrogen oxides contained in the exhaust gas is relatively low, exhaust gas having a low concentration of nitrogen oxides can be supplied to the greenhouse in each driving state of the internal combustion engine. .

  Further, a carbon dioxide concentration detection unit and a nitrogen oxide detection unit are provided in the greenhouse, and the carbon dioxide concentration in the greenhouse is increased in the greenhouse based on detection outputs from the carbon dioxide concentration detection unit and the nitrogen oxide detection unit. When the nitrogen dioxide concentration in the greenhouse is lower than the required carbon dioxide concentration range and is greater than or equal to the nitrogen oxide concentration range required in the greenhouse, the internal combustion engine is driven for stoichiometric combustion, and otherwise Is provided with a switching control unit that switches to drive the internal combustion engine to perform lean combustion, the internal combustion engine drive control method can be appropriately performed, while maintaining the drive state of the internal combustion engine as highly efficient as possible, The nitrogen oxide concentration in the greenhouse can be kept low.

〔Constitution〕
The heat from the internal combustion engine may be used for heating in the greenhouse,
While generating with the said internal combustion engine, you may use the electric power obtained by the said power generation in the said greenhouse.

[Function and effect]
In other words, if these configurations are adopted, the energy consumed by the internal combustion engine can be used not only in carbon dioxide but also in the greenhouse as heat and power, so that the entire system can be used efficiently and efficiently. became.

  Accordingly, the operation driving state of the internal combustion engine can be well controlled while maintaining the plant growth conditions in the greenhouse space easily and appropriately, so that the effective use of energy as a trigeneration also from the aspect of plant growth conditions From this point of view, a suitable greenhouse cultivation system can be provided.

It is the schematic of a greenhouse cultivation system. It is a flowchart of cultivation control of a greenhouse cultivation system.

  Below, the greenhouse cultivation system of this invention is demonstrated. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The greenhouse cultivation system of the present invention is configured with a cogeneration apparatus 1 provided in a greenhouse 2. The cogeneration apparatus 1 is provided with a generator 12 in a gas engine 11 as an example of an internal combustion engine to generate electric power, and an exhaust gas passage 13 through which an exhaust gas 11a generated from the gas engine 11 circulates, and the gas engine 11. Further, a cooling water flow path 14 for circulating engine cooling water 11b for cooling the exhaust gas 11a is provided, and exhaust heat is recovered from the gas engine 11 and the exhaust gas 11a by an exhaust gas heat exchanger 15 so that heat can be used. The fuel supply unit 16 for the gas engine 11 includes a fuel supply valve 16a that adjusts the ratio of fuel and air supplied to the gas engine 11 so that the combustion drive state of the gas engine 11 can be changed and controlled. The flow rate can be controlled by a control device 3 described later.

  The greenhouse 2 includes a cultivating unit 21 that cultivates plants in the greenhouse space 2a, and further includes a power consuming device 22 such as a power-driven heating device 22a, a ventilation device 22b, and illumination (light source for plant growth) for the cultivating unit 21. And the electric power generated by the generator 12 is configured to be controllable so that the greenhouse space 2a becomes an environment suitable for plant growth. Further, an exhaust gas flow path 13 of the gas engine 11 is connected to the greenhouse 2, and carbon dioxide in the exhaust gas 11a generated when the gas engine 11 is driven can be supplied into the greenhouse space 2a. .

  The greenhouse space 2a is provided with a carbon dioxide detector 23 for detecting the carbon dioxide concentration and a nitrogen oxide detector 24 for detecting the nitrogen oxide concentration.

  The exhaust gas flow path 13 of the gas engine 11 is branched by a flow path switching unit 17 to provide a lean combustion exhaust gas flow path 13A and a stoichiometric combustion exhaust gas flow path 13B. The exhaust gas flow path 13 of the gas engine 11 depends on the operating state of the gas engine 11. The exhaust gas flow path 13 is switched to allow the exhaust gas 11a to flow. The lean combustion exhaust gas passage 13A is filled with an exhaust gas purification unit 18A, and the stoichiometric combustion exhaust gas passage 13B is filled with a three way catalyst (hereinafter referred to as the first and second exhaust gas purification units). The exhaust gas 11a produced according to each combustion state of the gas engine 11 is purified with an appropriate purification catalyst corresponding to the nature of the exhaust gas 11a (18A for nitrogen oxides and carbon monoxide, 18B for It is configured such that carbon monoxide can be removed. Further, an exhaust gas heat exchanger 15 is provided on the downstream side of each exhaust gas purification unit 18A, 18B, and the high temperature exhaust gas 11a that has passed through both the exhaust gas purification units 18A, 18B is heat exchanged with the cooling water 11b, thereby While cooling to the temperature suitable for 2a, it is the structure which can collect | recover heat to the said cooling water 11b, and can supply to the said cultivation part 21 as the heat supply part 25.

  The carbon dioxide detector 23 and the nitrogen oxide detector 24 detect the carbon dioxide concentration and the nitrogen oxide concentration in the greenhouse 2 space and transmit the detection output to the control device 3. In the control device 3, the opening degree of the fuel supply valve 16 a is adjusted according to the outputs of the carbon dioxide detector 23 and the nitrogen oxide detector 24, and the operation driving state of the gas engine 11 is changed to lean combustion driving and stoichiometric. The flow path switching unit 17 is controlled to be switched according to the driving state of the gas engine 11.

  When the gas engine 11 is driven by lean combustion, the exhaust gas 11a branches the exhaust gas flow path 13 at the flow path switching unit 17 and flows through the lean combustion exhaust gas flow path 13A. The exhaust gas 11a flowing into the lean combustion exhaust gas passage 13A is purified by the first exhaust gas purification unit 18A, and is cooled by exchanging heat with the cooling water 11b in the exhaust gas heat exchanger 15, and reaches the greenhouse. In addition, when performing the combustion drive control of the gas engine 11 which will be described later, when the gas engine 11 is driven by lean combustion, there is a case where control is performed so that the exhaust gas 11a is not introduced into the greenhouse space 2a. The exhaust gas 11a can be discharged to the outside from the exhaust part 19 provided between the exhaust gas heat exchanger 15 of the lean combustion exhaust gas flow path 13A and the greenhouse 2.

  Further, when the gas engine 11 is driven by stoichiometric combustion, the exhaust gas 11a branches the exhaust gas flow path 13 at the flow path switching unit 17 and flows through the stoichiometric combustion exhaust gas flow path 13B. The exhaust gas that has flowed into the stoichiometric combustion exhaust gas flow path 13B is purified by the second exhaust gas purification unit 18B, is cooled by exchanging heat with the cooling water 11b in the exhaust gas heat exchanger 15, and reaches the greenhouse.

  The combustion drive control of the gas engine 11 is performed according to the flow shown in FIG.

  That is, when the carbon dioxide detection output from the carbon dioxide detector 23 provided in the greenhouse 2 exceeds the carbon dioxide concentration of 1500 ppm (# 1), it is not necessary to introduce the exhaust gas 11a into the greenhouse 2, and the control The device 3 throttles the fuel supply valve 16a to increase the air-fuel ratio, and the gas engine 11 is driven with high efficiency by lean combustion drive (# 2). Further, the exhaust gas 11 a is released to the outside from the exhaust part 19 and is not introduced into the greenhouse 2. Therefore, the carbon dioxide concentration in the greenhouse 2 does not increase any more.

  Next, if the plant in the greenhouse 2 consumes carbon dioxide by photosynthesis or the like, and the concentration of carbon dioxide in the greenhouse 2 decreases, it is necessary to introduce the exhaust gas 11a into the greenhouse 2; If the substance concentration (# 4) is low, the control device 3 still drives the gas engine 11 in lean combustion, the control device 3 throttles the fuel supply valve 16a to increase the air-fuel ratio, and the gas engine 11 While being driven with high efficiency (# 5), the exhaust gas 11a is introduced into the greenhouse 2 through the lean combustion exhaust gas passage 13A (# 6).

  If the lean combustion exhaust gas 11a is continuously introduced into the greenhouse 2 from the lean combustion exhaust gas passage 13A, the exhaust gas of the stoichiometric combustion is removed by the exhaust gas purification unit 18B although the concentration of nitrogen oxides in the exhaust gas of the lean combustion is originally low. Since the concentration is higher than the nitrogen oxide concentration, the nitrogen oxide concentration in the greenhouse 2 gradually increases. Therefore, when the nitrogen oxide concentration in the greenhouse 2 becomes 2 ppm or more (# 4), the control device 3 changes the driving state of the gas engine 11 to stoichiometric combustion drive (# 7). That is, the control device 3 opens the fuel supply valve 16a, lowers the air-fuel ratio, and changes the driving state of the gas engine 11 so that the power generation efficiency is reduced but the nitrogen oxide concentration in the exhaust gas 11a is lowered. To do. As a result, the exhaust gas 11a of the gas engine 11 reaches the second exhaust gas purification unit 18B filled with the three-way catalyst through the stoichiometric combustion exhaust gas passage 13A, and enters the greenhouse 2 as clean exhaust gas containing almost no nitrogen oxides. (# 6). Accordingly, the greenhouse 2 can be operated to reduce the nitrogen oxide concentration in the greenhouse 2 while continuing to supply carbon dioxide.

  In the above example, the inside of the greenhouse 2 is controlled so that the carbon dioxide concentration is 700 ppm to 1500 ppm, which is said to be suitable for the forcing cultivation of plants. Further, the nitrogen oxide concentration is controlled to be less than 2 ppm which does not hinder plant growth. The management values required in these greenhouses can be set as appropriate according to the type of plant.

  According to the present invention, the management of the greenhouse environment of the greenhouse cultivation system can be performed more precisely and finely, and the driving efficiency of the internal combustion engine can be maintained at a high level. It became possible to produce efficiently.

18A, 18B Exhaust gas purification unit 13 Exhaust gas passage 11a Exhaust gas 2 Greenhouse 11 Internal combustion engine

Claims (5)

An internal combustion engine drive control method for supplying exhaust gas containing carbon dioxide to a greenhouse by burning hydrocarbons through an exhaust gas flow path provided with an exhaust gas purification unit,
When the carbon dioxide concentration in the greenhouse is lower than the carbon dioxide concentration range required in the greenhouse and the nitrogen oxide concentration in the greenhouse is equal to or higher than the nitrogen oxide concentration range required in the greenhouse, the internal combustion engine While supplying to the greenhouse via an exhaust gas flow path provided with an exhaust gas purification unit provided with a three-way catalyst for purifying exhaust gas from the internal combustion engine,
When the carbon dioxide concentration in the greenhouse is lower than the carbon dioxide concentration range required in the greenhouse and the nitrogen oxide concentration in the greenhouse is lower than the nitrogen oxide concentration range required in the greenhouse, the internal combustion A drive control method for an internal combustion engine, which drives the engine in lean combustion and supplies it to a greenhouse via an exhaust gas flow path provided with an exhaust gas purification unit provided with an oxidation catalyst for removing carbon monoxide from the internal combustion engine. When the carbon dioxide concentration in the greenhouse is not lower than the carbon dioxide concentration range required in the greenhouse, the exhaust gas when the internal combustion engine is driven with lean combustion is discharged into a space other than the greenhouse in the exhaust gas passage. The internal combustion engine drive control method according to claim 1, further comprising an exhaust section. A greenhouse cultivation system having an exhaust gas flow path for supplying exhaust gas containing carbon dioxide discharged from an internal combustion engine fueled with hydrocarbons to plants in a greenhouse space,
The internal combustion engine is configured to be switchable between a lean combustion operation and a stoichiometric combustion operation,
A lean combustion exhaust gas channel and a stoichiometric combustion exhaust gas channel are provided in the exhaust gas channel,
An exhaust gas flow path switching unit that switches between the lean combustion exhaust gas flow path and the stoichiometric combustion exhaust gas flow path according to the combustion operation state of the internal combustion engine,
An exhaust gas purification unit provided with an oxidation catalyst in the lean combustion exhaust gas channel, and an exhaust gas purification unit provided with a three-way catalyst in the stoichiometric combustion exhaust gas channel,
While providing a carbon dioxide concentration detector and a nitrogen oxide detector in the greenhouse,
Based on the detection output from the carbon dioxide concentration detector and the nitrogen oxide detector, the carbon dioxide concentration in the greenhouse is lower than the carbon dioxide concentration range required in the greenhouse, and the nitrogen oxide concentration in the greenhouse Is provided with a switching controller that switches the internal combustion engine to stoichiometric combustion, and otherwise switches the internal combustion engine to lean combustion. Cultivation system. The greenhouse cultivation system according to claim 3, wherein heat from the internal combustion engine is used for heating in the greenhouse. The greenhouse cultivation system of Claim 3 or 4 which uses the electric power obtained by the said electric power generation in the said greenhouse while generating electric power with the said internal combustion engine.

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